Process of uniting copper to ferrous metals.



To all whom it may concern: i v Be it known that I, WILLIAM MARSHALL WILLIAM MARSHALL PAGE, CHESTER, PENNSYLVANIA.

PROCESS UNITING COPPER T0 FERROUS METALS.

1,171,066. 1 No Drawing.

PAGE, a citizen of the United States, residingat Chester, in the county of Delaware and State of Pennsylvania, have invented certain new and useful Improvements in Processes of Uniting Copper .to Ferrous Metals, of which the following is a specification.

This invention relates to processes of uniting copper to ferrous metals; and it comprises a process wherein a'body of copperiron alloy,- of relatively low iron content 1s,.

produced by the addition to molten copper, or to copper already containing iron, of suitable quantities of iron or steel in company with a deoxidizing agent such as phosphorus; a body of iron or steel is then brought into contact with the resulting molten copper-iron alloy-and is filmed or coated therewith, and a body of substan= tially pure copper is finally united to the alloy coating; all as more fully hereinafter described and as claimed.

In successful processes of uniting copper to steel or iron, the billet or other body of steel to be coated or clad is first brought into contact with .copper heated. considerably above its melting point to receive apreliminary film coating or linking layer to which a larger body of copper is subsequently united by casting or otherwise bringing cop per at or near ordinary casting temperatures into contact with such preliminary film coating. The temperature of the filming bath is such that, in spite of the fact that iron and copper do not have any arked tendency to unite integrally or weldt gether at temperatures around the meltin point of copper,

nevertheless at this higher or super-' rous metal base to which it is attached. Union having been thus attained, it is found in practice a comparatively simple matter to weld-unite to the copper-surfaced billet or other body of ferrous metal a body" of pure copper of any desired thickness,

there being no difliculty in thus welding copper to copper. Copper applied at ordinary Specification of Letters Patent. Paten ted Feb 8, 1916. Application filed June 17,1913. Serial No. 774,162.. 7 l

A preliminary or film coat of copperon iron or steel is facilitated if the copper of the filming bath contains iron iii-rather small proportions. In other words, the union of'copper with the ferrous metal base occurs more readily and certain other desirable advantages are secured, if a 'copper-ironralloy of low iron content be employed as the filming 'bath, rather than ordinary copper. On ac.- cdunt of this more ready union of iron with per, the temperature of thev filming, bath need not be so high as withsuchaordinary copper. In my'copendin prior application Serial No. 556,601, filed pril 20, 1910, this -idea disclosed broadly.- As to such disclosure, the present application is a continuation of said prior application.

The present application has to do with .im-- provements upon the process above described. The present process enables the.

a copper-iron alloy than with ordinary cop ready production and accurate control in composition of copper-iron alloys, of the type desirable in the preliminary filming bath with which the iron or steel base is first brought into contact.

It is diflicult under ordinary furnace con ditions to alloy iron or steel and copper and to control the composition of the resulting bath. Solid iron does not dissolve readily in molten copper unless the copper bath be heated to temperatures approaching or ex partic arly steel employed. Furthermore, wher the copper bath is heated directly by ceedirg l the melting point of iron or of the gas or oil firing as is customary in practice,

.it is practically impossible to avoid more or less pronounced oxidizing conditions in attaining the temperatures necessary. In order to obtain efiicient utilization .of fuel and intense heat some excess air must be used; Under such. conditionsmolten copper invariably contains some cuprous oxid. When iron is added to such a body of molten copper, since iron has a greater aflinity than copper foroxygen, there ispreferential or selective oxidation of the iron, part of the iron reducing the T'cuprous oxid with theformation of oxids of iron while the remainder is progressively oxidized by the furnace gases as longas there is any iron left in the bath. Iron also has a purifying action in removing other impurities, such as sulfur,

from thecopper. Copper is apt to take up some sulfur from thefurnace gases.

It is apparent therefore that the iron content of the bath is difficult to control and regulate under the conditions described. Such control and regulation are, however, of great importance where uniformity in final product is required as in the production of copper-clad steel wire. The conductivity of such wire must be a maximum and must also be uniform for commercial application in telephone and telegraph'lines and in other electrical work. Relatively slight variations of the conditions prevailing in the process, particularly as regards the composition and temperature of the filming bath, afl"ect the conductivity of the finished wire profoundly. And while high quality and uniformity of product are necessary, 1n

' commercial practice rapidity and efliciency of work are of course as necessary.

' Another disadvantage incident toexcessive oxidation of the ironin the molten bath arises from the fact thatwhen a billet is dipped into the bath, particles of iron oxids are apt to attach themselves to the surface of the billet, in spite of the fact that their specific gravity is less than that of copper, and thus prevent actual contact of the alloy or filming bath with the billet at such points. Oxids ofiron may also be formed in place by the oxidizing action of objects, as well as certain other advantages,

are attained according to the present process by the use of a powerful deoxidizing agent such as phosphorus employed, in conjunction with suitable additions of iron to the filming bath, in such manner that the iron content of said bath is brought to a certain approximately definite percentage and the composition of the bath is maintained substantially constant while a billet V of iron or steel is being immersed in the bath for a' suitable period of time to receive the desired alloy or film coating against which is to be subsequently cast a relatively thick layer of pure copper. In practice the iron' content of the bath should be relatively low. From 1 to 3 per cent. of iron -is'found. advantageous, around 2 per cent. being best, though these limits are'not rigid.

In carrymg out the present"process, any

suitable apparatus may be employed, but

hearth and is melted or maintained molten.

Whenfhe furnace is tilted into dipping position, molten metal flows into the dipping chamber or pocket which is of a depth and width suitable to accommodate the molten metal coming from the hearth to form a deep body into which the billet may be dipped. Assuming a furnace of this type to be employed, Twill now describe a typical embodiment of the present process as actually carried out in practice. A suitable amount of copper, say 15 tons, is melted in the heating chamber and the heating is continued until the molten copper is very fluid and lively. Suflicient iron or steel is added either at or prior to this time'to give about 2 after allowing for the necessary losses 1n melting down and dissolving the iron. The iron or steel may be added as such, or, conveniently, as copper clad steel scrap. The addition of material quantities of metals which would remain in the alloy bath, other than iron and copper, should be avoided however as. disadvantageous, since it is desired to obtain a copper-iron alloy or mixture which for practical purposes is substantially free of other elements. The iron need not be extremely pure of course, the quantities of the elements usually occurring as impurities or otherwise in the usual commercial grades of iron and steel doing no material harm. During this melting down and dissloving operation, it is unnecessary to go to great lengths to prevent oxidation of the iron. The dissolved iron shields thecopper fro-m oxidation and in so doing itself suffers oxidation in part; and a further portion is of course oxidized directly by the furnace gases. But this loss can be allowed for in adding the iron to the bath; and it ischeaper to operate in this way than to use the amount of iron theoretically required to produce the desired molten mixture and add phosphorus to afford protection against loss by oxidation. The latter method may be employed but about the only per cent. of iron in the molten mixture u advantage it offers is that smaller quantities of iron oxids are formed inthe bath. Such oxids as are formed by the addition of the bath of any particles of iron oxids which may have become entangled mechanically below the surface of the bath, and to hold the composition of the alloy bath substantially constant during the succeeding billetfilming step. I accordingly add a powerfuldeoxidant which will dissolve in the metal bath and diffuse therethroughrapidly.

Phosphorus ofi'ers the greatest advantages- In certain for this purpose in practice ca'sesother deoxidants may be us d, but to less.advantage. The amount of p osphorus phosphorus should be added to free the body of the bath from'oxids and to afford a certain excess available for protecting the metals of the bath from further oxidation ,for the brief period of time during which the filming operation can be accomplished. .One function of the phosphorus is therefore to act as a steadier for the composition of the bath and it does so at the expense of its own oxidation. As long as any free phosphorus remains in the bath, neither the iron nor the copper undergoes oxidation and the composition of the bath as regards these metals is constant.

The appearance of the scum or crust on the surface of the bath on tilting the furnace toexpose the metal *to the air for -'a minute or so affords a convenient indication as to whether or not suflicient phosphorus has .been added. A dark or black slag is afavorable indication, while a yellowish crust shows the presence of too large quantities of oxids of iron and the necessity foradding more phosphorus. When the alloy bath is of the proper cbmposition, a cast test piece shows a characteristic close grained silky fracture and is tough andhard to break.

The copper iron alloy bath having been I brought'to a definite composition, the furbath-and allowed to remain therein for a period of time depending somewhat on the size and temperature of the billet to be dipped' Operating with thefilming bath at approximately 2250 degrees F., or there, about, with a 300 to 400 pound billet the period of immersion should be in the neighborhood of 2 minutes.

" For handling the prepared and cleansed billet prior to its immersion and after it is filmed, I prefer to usea bottomless casing closed at the top and provided with means for admitting a reducing atmosphere such as acetylene or producer gas to its interior, within which the billet may be inclos ed and protected from the air. Means are pro- *vided forsuspending the billet in the casing and for lowering it ,therefrorh. into the filming bath. The casing may serve also as theside walls of a mold, after the filming,-

coat has been applied, into which the final or mainlayer of copper is cast around the filmed billet. A casing mold of this type is described in Patent 853,716. 'Still another form and one whichI find even more convenient is disclosed in my copending application, Ser. No. 607,338, filed Feb. 8, 1911.

After the billet has remained in the alloy bath a sufficient length of time to acquire the desired copper-iron 'alloyfilm, it is withdrawn from the bath into the protecting casing, gas being fed into t e casing continuously to maintain a reducingatmosphere bathing the filmed billet. The casing with the contained billet is then set on a mold bottom (1 suflicient pure copper, which has been elted in a separate furnace, is cast around the filmed billet. After the mold and its contents have COOlBQ SllfllClGIltlY, the mold sections are knocked apart and the clad billet is transported to soaking and re-heating furnaces preliminary to being rolled and drawn down into wire.

Work is facilitated by correlating the speed of operation with the sizes of billet and apparatus and their temperatures that at the moment of applying the second or cast-on coat, the exterior surface of the alloy film'is still liquid or soft. In the meantime, the alloy bath having cooled somewhat during the filming operation, it'is returned to the furnace ack into its original position. The alloy bath is again brought up to the proper temperature, the furnace is again tilted to cause themolten alloy mixture to flow back into the flipping pocket and the filming operation is performed on anotherebillet as previously described.

In order to keepthe composition of'the alloy bath sufficiently constant and to insure the absence of an undue amount of oxids in the bath it is necessary to frequently replenish the bath with additions of iron and phosphorus. 'The'heating of the alloy bath after the filming operation necessarily occasions more or less burning out of the iron. In practice it is often adhcjating chamber by tilting the. alloy visable to so replenish the bath at intervals of 4 to 5 minutes. These intervals corre' spond approximately to the'period of time" which separates the filnnng of any two successive billets, and it is convenient to add a small amount of iron immediately after each filming operation and just before the alloy furnace is tilted back into heating position. With each addition of iron, it is necessary to add a small amount of phosphorus to act as before in the role of a shielding agent for the iron and a steadier for the bath composition. Operating with the amount of copper here assumed I find that after each filming operation an addition of from 10 to 15 pounds of ,iron and from to 1 pound of phosphorus serves to keep the alloy bath at the desired composition and in the proper condition.

Not only does the phosphorus act as above described, but it also greatly facilitates the solution of the added-iron in the molten bath. As above stated, iron alone does not dissolve in copper with great ease, and espe-v cially where the temperature of the bath is "not run .up to an excessively high point.

But when phosphorus and iron are brought together in the bath the solution of the iron takes place with great rapidity and a uniform distribution of the'iron throughout the bath is readily effected, even where the temperature of the bath is not at the excessively high degree above noted. It is its protective functions. Where copper clad scrap is used for the additions of iron, a greater weight of such scrap must of course be employed in order to introduce the desired amount of iron. v

The ferrous metal body whose protection with copper is herein contemplated, while specifically hereinbefore referred to as a steel billet is of course not necessarily c'onfined to steel per se. The terminology employed is intended to include'iron and steel bodies of all kinds. The steel niay be a simple carbon steel or it may be any of the so-called alloy steels containing varying proportions of nickel, chromium, vanadium and the like. i

What I claim is 1 1. The process ofuniting'copper'to steel which comprises preparing a bath of a molten alloy or mixture of copper. and iron of approximately predetermined composi-- tion. contacting therewith a body of steel until said body acquires an adhering coating or film, removing said body of steel from contact Withsaid bath, and unit- 1 ing a body of substantially pure copper to the filmed steel body.

2. The process of uniting copper to steel which comprises preparing a bath of a molten alloy or mixture of copper and iron of approximately predetermined compost small, contactmg therewlth a body of steel until said body acquires an adhering coating tion, the proportion of iron being. relatively obtain an alloy or mixture of copper and iron, contacting said alloy or mixture in molten condition with 'a solid body of steel and maintaining such contact until said steel body is coated or filmed with the alloy or mixture, terminating the contact of the steel body with the molten mixture, and thereafter uniting a body of substantially pure copper to the filmed steel body.

4E. The process of uniting-copper .to steel which comprises treating molten copper with iron and a deoxidant to obtain a molten bath of a mixture or alloy of copper and iron, said'mixture being low in iron, dipplng a steel billet into said bath to. produce an adherent coating of copper iron alloy on sald billet, removing the billet from the bath, and casting substantially pure copper against the filmed billet.

5 The process of uniting copper to steel whlch comprises treating molten copper with iron and phosphorus to obtain a molten bath of a mixture or alloy of copper and iron, said mixture being low in iron,

dipping a steel billet into said bath to produce an adherent coating of copper iron alloy on said billet,removing the billet from the bath and casting substantially pure cop per against the filmed billet.

6 The process of uniting copper to steel which comprises treating molten copper with iron and phosphorus to obtain a molten alloy or mixture of copper and. iron comprising approximately between 1 and 3 per cent; of iron, said mixture being low in iron,

dipping a steel billet into said bath to produce an adherent coating of copper iron alloy on said billet, removing the billet from the bath, and casting substantially pure copper against the filmed billet.

The process of uniting copper to steel which comprises preparing a' molten bath of an alloy or mixture of copper and iron of approximately known composition, maintainlng said molten bath at relatively very h gh and fairly constant temperature, correctmg the composition of said bath by add- 1n g lron and phosphorus thereto, and dipping a body of steel thereinto to produce an alloy coating on said billet.

8. The process of uniting copper to steel which comprises preparing a molten bath of an alloy or mixture of copper and iron of approximately known composition, main-' taining said molten bath at relatively Very high and fairly constant temperature, correcting the composition of said bath by adding iron and phosphorusthereto, dipping a body of steel thereinto to produce an alloy' coating on said billet, and casting substantially pure copper against said billet.

9. In a process of coating metals, the method which comprises adding substantially pure iron and phosphorus to copper under melting conditions to obtain a molten alloy or mixture of copper and iron and dipping a steel billet in said bath to produce an adherent coating of copper-iron alloy on said billet.

In testimony whereof, I afiix my signature in the presence of two subscribing Witnesses.

WILLIAM MARSHALL PAGE. 

